The hypothesis that food intake during the preweaning period markedly influences the number of adipocytes of the adult has had great medical impact, but the validity of the hypothesis has not been tested rigorously in man and other primates. Since it is impossible to test the hypothesis in man, the major aim of the proposal is to test this hypothesis rigorously in the baboon. To this end, we subjected baboons to the following 4 preweaning regimens: 1) a breast-fed group; 2) a group fed an amount of infant formula that resulted in the same weight gain as breast-fed, thus termed "normal" fed; 3) an "overfed" group, fed 146% the amount of formula as the "normal" fed group; 4) an "underfed" group, fed either 64% or 78% the amount of formula as the "normal" fed group. At 4 months of age (at weaning), we changed the animals to a prepared baboon chow diet which simulates the cholesterol content and calories from fat of the average American diet. We sacrificed the baboons at 5 years of age at which time 17 fat depots were excised quantitatively. At present, the following analyses are underway: 1) the determination of total fat content and fat cell number of each excised depot; 2) the determination of the fat mass, total fat cell number and lean body mass of each baboon; 3) the grading of atherosclerotic lesions of the excised arteries. All of the nutritional manipulations have been completed and all of the animals have been necropsied. This is a request for one year of further support in order to complete the laboratory analytical work and the data analyses. In addition to testing the adipocyte number hypothesis, we propose to test the following other hypotheses from the data generated: 1) preweaning nutrition influences the fat mass of young adult baboons; 2) preweaning nutrition influences the lean body mass of young adult baboons; 3) preweaning nutrition influences the extent of atherosclerotic lesions in young adult baboons. This research proposal relates to our long-term goal of understanding the aging process and its relation to age-related disease by providing definitive information on the possible role of early nutrition in the age-related problems of adiposity and atherosclerosis.